How are Emperor penguins adapted to survive
in Antarctica? The largest of all penguins
by a considerable margin. Animals of the very deep south
and the only large animal that remains in Antarctica
in the depths of the long dark winter night, the time
when it not only survives but breeds and rears young.

Of all animals on earth, the Emperor Penguin has
a claim on being one that endures some of the most extreme conditions.
To do this they have many adaptations that can be categorized
as follows:

Anatomical - Structures of the body.

Behavioural - The manner in which animals
move and act.

Physiological - The internal functions
of the animal from biochemical, to cellular, tissue, organ
and whole organism levels.

Emperor Penguin
Anatomical Adaptations

Large size -
helps
to retain heat, Emperors
are twice the size of the next biggest penguin, they are able to survive the extreme cold temperatures
of winter without feeding for extended periods. A large
size, with low surface to area ratio slows down the loss
of heat, a simple shape and flippers that can be held close
to the body also reduce surface area on land.

Short stiff tail - on land the
tail forms a tripod when the penguin rocks back slightly
on its heels, this gives the minimum contact area with the
ice or snow to prevent heat loss.

Chicks have soft down for insulation,
this is a more effective insulator on land than
the feathers that the adult birds have, but are of little
use in the sea, they must moult and grow feathers before
they can swim.

Highly specialized bird skeleton
a very upright gait, short neck, short legs and
long body.

Powerful claws on the feet to help
to gain a grip on snow, ice or rock when emerging from the
ocean or when tobogganing.

Emperor Penguin
Behavioural Adaptations

Huddle together to conserve heat,
without this behaviour they wouldn't be able to survive the Antarctic
winter. The penguins shield each other from the wind by
taking it in turns to be on the outside or inside of the
huddle, they stand very close to each other but don't actually
touch in order to get the maximum insulation from their
own feathers and those of the penguins around them.

Unlike other penguin species, they are
not aggressively territorial, this allows for huddling
to take place.

No nest is made, the eggs and then chicks
sit on the parents feet to keep them off the ice,
they are covered by a fold of skin to keep them
warm and are carefully moved from one parent to the other
when they are small to allow the parents to take turns to
go fishing.

They breed during the depths of the Antarctic
winter, so the chicks are large enough to become
independent during the summer abundance of food, other smaller
penguin species are able to grow quickly enough when breeding
in the spring.

Males will sleep for 20-24 hours a day
while incubating the egg and waiting for the female to return,
this conserves energy.

When the female lays her egg, it is passed
over to the male, the female then goes to sea and
will not return for an average of 115 days but up to 120.

Emperor Penguin
Physiological Adaptations

A complex heat exchange system that
allows 80% of heat in the breath to be recaptured in the
nasal passages.

Heat exchange systems in the flippers and legs
keep these regions cooler than the body core
and prevent what otherwise would be a disproportionate
heat loss from these areas.

They can dive to a depth of 1,800 feet
(550 meters) and hold their breath for up to 22 minutes,
so are able to reach and exploit food resources
that other birds can't reach.

The normal resting heart-beat
is about 60-70 beats per minute (bpm), this goes
up to 180-200 bpm before a dive as they load up with oxygen,
as they hit the water, the rate drops to 100 bpm immediately,
slowing to 20 bpm for most of the dive.

Males can make "milk" in the
oesophagus which can be used to feed chicks in the winter
before the female arrives back from fishing.

Males can fast for over 100 days
while incubating the egg and awaiting the return
of the females.